除国库券外，其他证券投资或多或少都存在一定的违约风险。 ( )
参考答案：错
解析： 股票投资不存在违约风险。
Tony ____ the invitation, otherwise he would have attended your birthday party.
A．couldn’t have received
B．mustn’t have received
C．needn’t have received
D．shouldn’t have received
与1型糖尿病有关的是（）与Graves病无关的是（）
A.HLA抗原
B.抗独特型抗体
C.独特型抗体
D.甲状腺刺激性抗体（TSAB.
E.葡萄糖激酶基因
